(-) Strictly with regard to meaning, "あそこ" and "あちら" are exactly the same, right? (of course, "あそこ" also has a slang meaning).
(-) Isn't "あちら" used more in writing? "あそこ" used in speaking?
(-) Isn't "あそこ" used in speaking because it sounds more pleasant? I am a native English speaker, and the "soft o" sound is pleasing to my ear and can be said very quickly. Does anyone agree, or am I crazy to say this?
(-) "あちら" would be the only appropriate option in formal conversations, right?
While I've heard "こちら" and "そちら" a lot, I've never heard "あちら". In fact, I had to check in my dictionary to verify it is even a word. Answers to these questions will help me decide about incorporating "あちら" into my speaking.